<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <!-- 8. 获取<p class='demo'> hello JavaScript</p>内部文案 -->
    <script>
        let str = "<p class='demo'>hello JavaScript</p>"
        let reg = /^\<.+\>(.+)\<.+\>$/
        let str1= str.replace(reg,function(match,$1){
            return $1
        })
        console.log(str1)

    </script>
</body>

</html>